Psychology - Unit 3&4

Sleep

A regularly occurring altered state of consciousness characterised by reduced awareness and unique brain-wave patterns.

Consciousness

Awareness of internal and external stimuli, existing on a continuum from focused wakefulness to deep sleep.

Normal Waking Consciousness (NWC)

The state of being awake and aware of one’s thoughts, feelings and environment.

Altered State of Consciousness (ASC)

Any state distinctly different from NWC in awareness, thinking, emotions or self-control.

Naturally Occurring ASC

An altered state that happens without external aid, e.g., sleep, dreaming, daydreaming.

Induced ASC

An altered state intentionally produced by aids such as drugs, meditation or hypnosis.

Psychological Construct

A concept created to describe processes that are inferred from behaviour or measurements but not directly observable.

Electroencephalography (EEG)

Technique that detects, amplifies and records electrical activity of the brain via scalp electrodes.

Electromyography (EMG)

Recording of electrical activity of muscles to monitor changes in movement and tone during sleep.

Electro-oculargraphy (EOG)

Method for measuring eye movements by tracking electrical activity of eye muscles.

Sleep Diary

A self-report log of sleep and waking activities kept over several days to assess sleep patterns.

Video Monitoring

Visual recording of a sleeper to observe posture, movements, breathing or parasomnias.

Brain Waves

Rhythmic electrical impulses of the brain, measured in frequency and amplitude.

Beta Waves

High-frequency, low-amplitude brain waves typical of alert wakefulness and REM dreaming.

Alpha Waves

Moderate-frequency brain waves present during relaxed wakefulness with closed eyes.

Theta Waves

Medium-frequency waves associated with drowsiness, early sleep (N1) and creative wake states.

Delta Waves

Low-frequency, high-amplitude waves dominant in deep NREM stage 3 sleep.

Circadian Rhythm

A biological cycle lasting about 24 hours, e.g., the sleep–wake cycle.

Ultradian Rhythm

A biological cycle shorter than 24 hours, such as the 90-minute sleep cycle.

Suprachiasmatic Nucleus (SCN)

‘Master clock’ in the hypothalamus that regulates circadian rhythms using light information.

Melatonin

Hormone from the pineal gland that promotes sleepiness; secretion peaks at night.

REM Sleep

Sleep with brain activity resembling wakefulness and muscle atonia; most dreaming occurs here.

NREM Sleep

Non-Rapid Eye Movement sleep comprising stages 1-3, with progressively deeper physiological relaxation.

Sleep Cycle

A roughly 90-minute sequence of NREM followed by REM sleep that repeats through the night.

Hypnogram

Graphical representation of sleep stages across a sleep episode.

Sleep Onset

Transition from wakefulness to sleep; often begins with NREM stage 1.

Sleep Latency

The time taken to fall asleep after intending to sleep.

NREM Stage 1 (N1)

Light sleep lasting 1–7 minutes; easily awakened; may include hypnic jerks.

NREM Stage 2 (N2)

Moderate sleep marked by sleep spindles and K-complexes; forms about 50% of total sleep.

NREM Stage 3 (N3)

Deep sleep dominated by delta waves; highest arousal threshold; critical for restoration.

Sleep Inertia

Grogginess and impaired performance immediately after waking, especially from deep sleep.

Partial Sleep Deprivation

Getting less sleep (quantity or quality) than needed over one or more nights.

Total Sleep Deprivation

Going without any sleep for 24 hours or longer.

Sleep Debt

Cumulative loss of sleep that must be ‘repaid’ to return to baseline functioning.

Affective Functioning

The ability to regulate and express emotions, impacting mood, emotional reactivity, and social interactions; often impaired by sleep deprivation.

The CNS

made up of the brain and spinal chord.

It coordinates all incoming sensory information and initiates outgoing messages.

The PNS

made up of all the nerves outside the CNS.

It carries the messages between the CNS and muscles, organs and glands throughout the body.

How many subdivisions of the PNS is there, and what are they?

There are two subdivisions of the PNS, the somatic nervous system and the automatic nervous system.

Somatic nervous system

carries sensory (afferent) information to the CNS

it involves motor (efferent) neurons in the somatic nervous system and are responsible for voluntary movements

Automatic nervous system

controls the body’s internal environment in an self-regulating manner

Sympathetic nervous system

dominant in response to perceived threats and stressful psychological or physiological stimuli

• examples:

• dilated pupils

• increase heart rate

• breathing

Parasympathetic nervous system

Has two main functions:

• maintaining a balanced internal state otherwise known as homeostasis

• counterbalancing the functions of the sympathetic nervous system by lowering arousal and restoring body to a calm state after a threat has passed.

Conscious responses

responses that require energy and usually involves input from the CNS and can involve decision making or choices

examples:

• putting on a jumper when you feel cold

Unconscious responses

any response to nervous system that does not require awareness

example:

• blinking, sneezing or coughing

Spinal reflexes

involuntary and unconscious response to a stimuli involving the spinal chord and happens without input from the brain

example:

• taking your hand away from a hot subject

Neurons

basic blocks of the nervous system

used to communicate information around the body. There are three types:

• sensory

• motor

• interneurons

Sensory (afferent neurons)

transmit information from the body to the brain

Motor (efferent neurons)

transmit information from brain to body

Interneurons

communicate between sensory and motor neurons

SAME

• S: sensory

• A: afferent

• M: motor

• E: efferent

Parts of neuron

   

Neuron: dendrite

receives incoming neural messages

Neuron: soma

the body of the neuron, containing the nucleus with the genetic material for the neuron

Neuron: axon

pathway down which the neural message travels

Neuron: myelin sheath

fatty tissue that encases the axon to aid in speed of transmission

Neuron: axon terminals

exit pathways for neural messages to make their way to the next neuron

Neuron: terminal buttons

releases a chemical substance known as neurotransmitter to a receiving neuron for communication purposes (also known as synaptic knobs)

What process do neurons use to communicate and what do they use?

Neurons communicate through a process called neurotransmission which uses electrochemical energy

Process of neurotransmission

1. neural impulse: runs from the dendrite down the axon to the axon terminals

2. terminal buttons: then release a chemical substance (chemical energy)

3. chemical substances: known as a neurotransmitter, crosses the synapse

4. The neurotransmitter is then picked by the receiving neuron through dendrites

A neuron has a _______ ______ when not activated

Resting potential

Action potential

also known as electrical impulse, is initiated by the soma and travels along the axon towards the axon terminals

Neurotransmitters

specialized chemical messengers, they transmit information from one neuron to the next (transported in the axon and release at the synapse)

Neurotransmitter

There is a tiny space between neurons called a synapse where neurotransmitters are release by the terminal buttons, before moving onto the next neurons (through dendrites)

Excitatory neurotransmitters

increase the likelihood that the postsynaptic neuron will fire.

The main excitatory neurotransmitter in the neuron system is glutamate

Glutamate

plays an important role in learning and the formation of memories in the brain. 

Inhibitory neurotransmitters

decrease the likelihood that the postsynaptic neuron will fire and action potential.

The main inhibitory neurotransmitter in the nervous system is gamma-aminobutyric acid (GABA) 

Neuromodulators

subclass of neurotransmitters, they are chemical modules just like neurotransmitters.

Dopamine as a modulator

Dopamine is a multifunctional neurotransmitter

both excitatory and inhibitory effects that is involved in many CNS functions. 

Serotonin as a modulator

only has inhibitory effects

can help counterbalance excessive excitatory effects of other neurotransmitters, as GABA does with glutamate. 

Synaptic plasticity

results in a strengthening or weakening of connections based on activity levels

Long term potentiation 

Relatively permanent strengthening of synaptic connections from repeated activation of a neural pathway 

Long term depression

Opposite of LTP, involves relatively permanent weakening of synaptic connections

Sprouting

creation of new extensions on a neuron to allow it to make new connections with other neurons.

This occurs through the growth of nerve endings (sprouts) on axon

Rerouting

occurs when new connections are made between neurons to create new neural pathways 

Pruning

elimination of weak, ineffective or unused synapses

Stressor

Any event that causes stress is referred to as a stressor.

Internal stressors

both the physical pain from an injury and the high expectations you have of yourself are internal.

External stressors

sources of stress that originate outside of an individual.

They include environmental events and social cultural stressors:

Acute stress

stress that lasts for a relatively short time

Chronic stress

stress that continues for a prolonged period of time

Distress

form of stress characterised by a negative psychological state

Eustress

form of stress characterised by a positive psychological state

Flight-or-fight or freeze

an automatic, biological response to a perceived stressor

Flight

which involved avoiding or escaping the stressor

Fight

which involves dealing with the stressor directly

Freeze

immobilisation of the body such as minimising movement or vocal sounds to avoid detection

Chronic stress - cortisol

• Primary stress hormone

• Involved in acute and chronic stress

• Acts more slower with lasting effects 

• Turns off all body systems not required to deal with the stressor

Gut brain axis

A bidirectional (two way) communication link between the central and enteric nervous systems 

Enteric nervous system 

• Subdivision of the autonomic nervous system

• Directly connected to the CNS 

The two way communication that occurs between the enteric nervous system and the CNS happens

Vagus nerve: 

• One of the body's biggest nerve 

• Connects brain to organs in the autonomic nervous system

• Runs from brain to colon

• Sends messages from the gut to the brain including pain and discomfort 

Gut microbiota

• System of microorganisms 

• Includes bacteria, fungi and viruses

• They can communicate with each other, therefore microbiota can also affect mental processes and behaviour

Gut dysbiosis

an unbalanced gut microbiome, either in number or type of microbiota

What did the GAS model measure

Hans Selye who made the GAS model

• Shows the immediate and long term effects of stress

• Most researched with rats

• Observed pattern of change

GAS model: Stage 1: Alarm reaction

• When the person first becomes aware of the stressor 

• Two substages: shock and countershock 

• Shock: temporary state, ability to deal with stressor falls below normal levels

• Countershock: body rebounds, sympathetic nervous system is activated, resistance to stressor is increased

GAS model: Stage 2: Resistance

• If stress isn’t dealt with immediately, energy is still required, the body continues to respond to cope with the stressor

Unnecessary physiological processes shut down (e.g. sex drive, digestion, menstruation etc.) so energy can be used on dealing with the stressor

Stage 3: Exhaustion

• If stress is not dealt with in the resistance stage the body can reach exhaustion

• Stress hormones are depleted

• Exhaustion symptoms: fatigue, sleep disturbances, severe loss of concentration, vulnerability to anxiety attacks, irritability, depressed mood, jumpiness and crying spells.

• Exhaustion symptoms over a long period: High blood pressure/hypertension, heart disease, gastrointestinal problems. 

• Can be permanent or death can occur

Strengths and limitations of GAS Model

Strengths:

• identifies biological processes

• Evidence of relationship between stress and illness

Limitations:

• Research was not conducted on humans

• Doesn’t account for individual differences and psychological factors

Lazarus and Folkman model - Primary appraisals

Primary appraisal:

• outcome of a primary appraisal is a decision about whether the event is irrelevant, benign–positive or stressful - if stressful 

additional appraisals follow

• harm/loss — an assessment of how much damage has already occurred (e.g. ‘I have lost my job’)

• threat — an assessment of harm/loss that may not have yet occurred but could occur in the future (e.g. ‘I mightn’t be able to afford the rent’), 

• challenge — an assessment of the potential for personal gain or growth from the situation (e.g. ‘I’ll get any other job I can and will learn to budget and save money’).

Lazarus and Folkman model - Secondary appraisals

Secondary Appraisal

• an evaluation of our coping options and resources for dealing with the event.

• Resources are either adequate or inadequate

• coping options are either internal (e.g. strength and determination) or external (e.g. money and support from family or friends).

Strengths and limitations of Lazarus and Folkman's model

Strengths:

• Focus on psychological

• observed people (not animals like GAS)

Weaknesses:

• Lack of evidence (subjective)

• overlooks physiological responses to stressors.